Results 81 to 90 of about 1,407 (268)
Ultrahigh Pressure Metamorphism: Cambridge Topics in Petrology
Eos, Transactions American Geophysical Union, 1996 The field of ultra‐high pressure metamorphism (UHPM) emerged only 12 years ago when microscopic relics of coesite were found in crustal rocks that had been metamorphosed during subduction related to continental collision. Coesite‐bearing metamorphic rocks were soon found elsewhere, and then metamorphic microdiamonds were discovered.
openaire +2 more sources
Investigation and reclassification of four mesosiderites—Implications for their formation
Meteoritics &Planetary Science, EarlyView.Abstract Mesosiderites are rare, differentiated meteorites, so‐called stony‐iron meteorites—they are impact breccias composed of an unusual mix of crustal basalt and pyroxenite, core‐derived metal, but no mantle materials. This odd mixture makes their origin enigmatic and has inspired many different formation theories over the last several decades ...
Gabriel Zachén +4 more
wiley +1 more source
Post-Hercynian ultrahigh-temperature tectono-metamorphic evolution of the Middle Atlas lower crust (central Morocco) revealed by metapelitic granulite xenoliths [PDF]
Solid EarthThe study of metapelitic sillimanite- and garnet-bearing granulite xenoliths brought to the surface by the basanite of the 650 ka Tafraoute maar shed new light on the lower crust of the Tabular Middle Atlas (Morocco).
A. El Maz, A. Vauchez, J.-M. Dautria
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Petrography of phosphates in CI and CY carbonaceous chondrites
Meteoritics &Planetary Science, EarlyView.Abstract Phosphate minerals are significant carriers of volatiles (e.g., OH) and halogens in chondritic material; however, their origin in most groups of carbonaceous chondrites remains poorly characterized. We have determined the abundance, morphology, texture, and composition of phosphate grains in aqueously altered CI chondrites and in hydrated and ...
C. S. Harrison +3 more
wiley +1 more source
Journal of Economic Geology, 2014 Introduction Geological background Ophiolites have played a major role in our understanding of Earth’s processes ranging from seafloor spreading, melt evolution and magma transport in oceanic spreading centers, and hydrothermal alteration and ...
Farhad Ghaseminejad, Ghodrat Torabi
doaj
Meteoritics &Planetary Science, EarlyView.Abstract Angrites and eucrites are among the oldest basaltic rocks in the solar system. However, the shock histories of these meteorite groups differ markedly, as most angrites show little to no evidence of shock metamorphism. While some angrites exhibit weak wavy extinction in olivine, indicative of low‐level shock, only two—Northwest Africa (NWA ...
Atsushi Takenouchi +4 more
wiley +1 more source
The fall of the Haag (LL4‐6) chondrite breccia—Just 8 years after the nearby fall Stubenberg (LL6)
Meteoritics &Planetary Science, EarlyView.Abstract On October 24, 2024, an impressive fireball was visible over Austria. After the possible strewn field was calculated, the first sample of the Haag meteorite, with a mass of 8.76 g, was discovered on November 2, 2024, 8 days after the fireball event. Four more samples were found afterward putting the total sample mass at about 151 g.
Addi Bischoff +25 more
wiley +1 more source
Journal of Economic Geology, 2015 Introduction Hornblende-bearing gabbroic rocks are quite common in subduction-related magmatic suites and considered to represent magmatic differentiation process in arc magmas (Heliker, 1995; Hickey-Vargas et al., 1995; Mandal and Ray, 2012).
Seyed Masoud Homam
doaj
Journal of Economic Geology, 2017 Introduction Dehnow-Abid area is a part of the geological map of Eshghabad with scale 1:100000 (Aghanabati, 1994) that is located about 20 kilometers northeast of Eshghabad and in the coordinates of 57° 6´ 0" to 57° 10´ 0" eastern longitude and 34° 28 ...
Omid Yazdanpanah, Ali Akbar Hassannezhad
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